Method of and apparatus for bright-annealing copper and brass tubes.



J. A. MOORHEAD.

METHOD OF AND APPARATUS FOR BRIGHT ANNEALING COPPER AND BRASS TUBES. APPLICATION FILED MAR. 28, 1918.

1,292,352. Patented Jan. 21,1919.

PM NTO aw 7 M ATTORN Y5 JDHN ALSTON MOQRHEAD, OF SE'W'ABEN, NEJI' JIEESEZ.

' Application filed march as, me.

To all whom. it may concern:

Be it known that I, JOHN ALs'roN Moon- HEAD, a citizen of the United States, residing at Sewaren, in the county of Middlesex and State of New Jersey have invented certain new and useful Improvements in Meth- ()(lS of and Apparatus for Bright-Annealing Copper and Brass Iubes, of which the following is a full, clear, and exact description.

The invention upon which is based this application for Letters Patent was primarily designed for annealing brass and copper tubes, and it will be herein described as applied to that particular purpose. By so doing, however, I intend to place no limita tion on its scope, but assume that all other purpose which it is capable of carrying out of a kindred nature will be regarded as contemplated and covered whether specifically referred to or not. The art in other words to which the invention pertains is now so well understood as to make it unnecessay to set forth in any detail all of the specific objects which its use and application may attain.

The present methods of annealing such iubes are slow and expensive. The apparatus required is more or less complicated and cumbersome, and the treatment and manipulation of the tubes during and after the annealing process proper involve considerable labor, time and outlay.

I have found that all these olbjecti-ons may be in large measure avoided by providing as the source of heat a powerful alternating current coil in the form of a long tube, through which, when properly constructed, the tubes may be progressively and continuously forced, in a non-oxidizing atmosphere, and thereby rapidly and perfectly annealed since they constitute a short closed secondary circuit for the primary coil which will raise them quickly to the proper annealing temperature. After the tubes issue from the heating coil they are immersed in a tank of water or other cooling liquid before they are permitted to meet an oxidizing atmosphere.

In the accompanying drawing I have illustrated a simple and convenient form of apparatus by means of which this process may be carried out, and I now refer thereto for a specific description of the improvement.

Figure 1 is a view in elevation and part Specification of Letters Patent.

Patented Jan. 21, 1919.

serial No. 5325,1939.

section of the complete apparatus capable of carrying out the invention.

Fig. 2 is a diagrammatic sectional view of the sectional view of the receiving tank. Flg. 3 is a top plan view of the tank.

Fig. 4: is a longitudinal section of the heating coil and tube and Fig. 5 is a cross section of the coil.

With the special character of the winding, sectional area of the conductors comprising the coil, or with the frequency of the alternating current employed, or the means of producing the current, the present invention is not directly concerned, as anyone skilled in the art will be able to select and apply such conditions in this regard as will meet the requirements of any particular case. I wish, however, to provide for a heavy alternatin current and to prevent, as far as practica le, the loss by radiation of the heat developed by the coil, and for this purpose I employ a substantially air tight tube A of any suitable highly refractory non-magnetic, non-conducting material, and which may be fifteen or more feet in length, around which I wind a layer of mica or other poor conductor of heat 13.

For purposes of cooling the coil as far as may be necessary I then apply raised ribs C upon which the coil D is supported. Air or oil may be passed through the space thus Provided between the coil and the heat non-conducting wall B.

The coil D is supported in an inclined position on a frame E and the tube A is extended in a tube F which may be of any convenient or suitable material and which leads into a water tank G below the surface of the water so that the forward end of the tube is air sealed.

A pi e H is connected with the tube F and throug it a supply of steam, carbonic dioxid or other non-oxidizin atmosphere or gas is admitted to the interlor of the coil or the ipe A.

en tubes are to be annealed they are progressively and continuously passed through the tube A, most conveniently by pushing them forward by the introduced tubes in the rear, which acting as short circuited secondary conductors of low resist-.

ance for the coil D currents are developed in them which raise them rapidly to a sufliciently high temperature for the purpose.

In the atmosphere of steam they are not -immersion in the tank. To facilitate their proper immersion they are forced along a shelf K, having a diagonal rib L which d1- rects the tubes over the edge of the shelf and causes them to fall in a pile on the bottom of the tank.

When a suficient number of tubes have accumulated in the tank they may be lifted out by chains M as indicated in Figs. 2 and 3.

The annealing process carried out by the use of the above described or other similar apparatus constitutes an advance in this art. The time required for complete and perfect annealing is very greatly reduced. In fact, I .have found that about one thousand pounds of copper, under the heating of. a currentof less than forty kilowatts may be annealed by the process in one hour. After they have passed through the tubes and been cooled they are" thoroughly annealed and present a bright and soft surface. 1

I am aware that metal bodies have been heated electrically and otherwise in a nonoxidizing atmosphere, such as steam, for the purpose of annealing them or producing other presumed eflects thereon, and this I do not claim, but what I regard as of my invention and desire to secure by Letters Patent is 1. The continuous process herein described of annealing copper or brass articles in the form of extended tubes, which consists in progressively passin a number of the same through an active a ternatingcurrent coil of corresponding length and theremesses by, by the development of induced currents therein, heating them to a temperature sufiioient for annealing the same, maintaining within the coil a non-oxidizing atmosphere, and immersing the tubes after their passage through the coil and before leaving such atmosphere in a body of cooling fluid.

2. The method of continuously annealing long copper or brass tubes which consists in progressively and continuously passin. a number of the same through an extended active alternating current .coil, and thereby heatingthem to the proper annealing temfiflrature by the development therein of inced currents, introducing into the interior of the coil a non-oxidizing atmosphere, and immersing the heated tubes in a cooling medium before they leave such atmosphere.

3. The apparatus herein described for continuously annealing copper or brass tubes, comprising in combination an extended alternating current primary coil, a substantially air tight non-conducting, nonmagnetic refractory tube surrounded by said coil, an extension of such tube terminating in a body of cooling medium below the surface thereof, means for introducing into the tube a non-oxidizing atmosphere, and means which permit long copper or brass tubes to be passed progressively and continuously through the coil so as to be heated to the proper annealing temperature by the development therein of induced currents and into the cooling medium without leaving the non-oxidizing atmosphere.

In testimony whereof I aflix my signature.

JOHN ALSTON MOORHEAD' 

